kherron@ms.uky.edu (Kenneth Herron) (06/08/91)
Over in .applications someone asked about a program called speedup which
changes the head step rate on floppy drives. I did a rewrite of this
program some time ago and (having been reminded) am wondering about
something.
The program modifies a longword 11 bytes from the beginning of the
device's trackdisk unit record; this is a private area beyond the end
of the TDUPublicUnit structure. The TDUPublicUnit structure also
contains two longwords for the step delay and head settle time, but
while I was hacking these fields always contained large negative numbers
(or something large anyway, I don't recall exactly). Clearly these
fields don't contain the step and settle delays, so how are they used?
And what value is actually stored at the 11th longword?
No flames about modifying private data please; I can't find *any*
documentation about the public fields and I never released the thing
anyway.
FYI: I can change the step(?) delay from 3000 ms down to 1900 ms without
problems; around 1800 it gets unreliable. The biggest benefit is that
the drives make less noise.
--
Kenneth Herron kherron@ms.uky.edu
University of Kentucky +1 606 257 2975
Department of Mathematics "So this won't be a total loss, can you make
it so guys get to throw their mothers-in-law in?" "Sure, why not?"bj@cbmvax.commodore.com (Brian Jackson) (06/09/91)
In article <1991Jun8.001706.13497@ms.uky.edu> kherron@ms.uky.edu (Kenneth Herron) writes: >Over in .applications someone asked about a program called speedup which >changes the head step rate on floppy drives. I did a rewrite of this >program some time ago and (having been reminded) am wondering about >something. > >FYI: I can change the step(?) delay from 3000 ms down to 1900 ms without >problems; around 1800 it gets unreliable. The biggest benefit is that >the drives make less noise. And quieter drives (this is pretty much only a problem on the older A1000's) is pretty much the only value. I used this on my A1000 and, after I ran a few benchmarks on the thing, I found that any performance gains were very small indeed (essentially non-existant.) It's probably harmless enough for the purpose of quieting noisy drives (though I may be corrected by the DOS folks) but it's probably worthless for any 'preformance' purposes. Caveat: I have not used this on anything but an A1000 so ... >Kenneth Herron Brian ----------------------------------------------------------------------- | Brian Jackson Software Engineer, Commodore-Amiga Inc. GEnie: B.J. | | bj@cbmvax.cbm.commodore.com or ...{uunet|rutgers}!cbmvax!bj | -----------------------------------------------------------------------
ttr1415@helios.TAMU.EDU (Thom Robertson) (06/14/91)
I am now using the Speedup program on my Amiga 1000 with full success. Yes, the only use for it is to quiet the drives down, but considering how old and noisy my drives are, this is a boon. *interestingly enough*, I took my Speedup-installed Workbench over to two freinds houses, and booted thier A500's with it. Even though one was a very old 500 (as 500s go) and the other was brand spanking new, both could not handle the step speedup, leading of course to interminable "disk error" messeges. Considering how old my 1000 is, this is VERY interesting... Thom Robertson P.S. While Speedup quieted my drives, the A500 drives sounded like blenders!